Ogawa was one of the few junior officers who knew of the Cardassian defector Joret Dal's presence aboard the Enterprise, as she helped Dr. Crusher treat his serious injuries. She was ordered not to discuss what she knew of Joret with anyone. (TNG: "Lower Decks")

Alyssa was friends with several other junior officers and civilians on the ship, including Sam Lavelle, Taurik, the late Sito Jaxa, and Ten ForwardwaiterBen. The group often played poker together. Sito departed the Enterprise on a covert mission with Joret Dal in 2370. Lavelle asked Ogawa if she knew any details about the mission, but Ogawa refused to reveal any information. Ogawa was saddened and upset when Sito was lost while returning from the mission. Lavelle felt guilty for accepting a promotion that he competed for with Ensign Sito, but Ogawa assured him that Sito would have been proud and happy for him. (TNG: "Lower Decks")

Beverly Crusher also considered Ogawa a friend. Beverly took interest in Alyssa's love life (TNG: "Imaginary Friend", "Attached") and was concerned when she noticed Ogawa's future husband, Andrew Powell, with another woman in Ten Forward shortly before they announced their engagement. (TNG: "Lower Decks")

Ogawa risked her own career when Dr. Crusher was relieved of duty for performing an autopsy on Dr. Reyga, violating the Ferengi death ritual and the Prime Directive. Crusher wanted to continue investigating, and was unable to access the needed autopsy files. Ogawa used her authorization to provide Crusher with the information, realizing that the vindication of Reyga and his work on the metaphasic shielding was very important to Crusher. (TNG: "Suspicions")

Ogawa dated Ensign Markson in early 2370, a relationship which became the subject of gossip between Dr. Crusher and Captain Picard. (TNG: "Attached")

Ogawa began seeing Lieutenant Andrew Powell later that year. Around the time of midyear crew evaluations, Alyssa worried that she and Andrew were growing apart. He began putting in many overtime hours and the couple did not spend much time together. However, Andrew proposed to her, much to her surprise and delight. They announced the engagement after the evaluations. (TNG: "Lower Decks")

The couple conceived a child shortly thereafter. The baby saved the life of the entire Enterprise-D crew when the ship was ravaged by Barclay's Protomorphosis Syndrome. Commander Data was able to extract natural immune barriers in the amniotic fluid from the pregnancy, which was used to cure the condition. During the crisis, Ogawa de-evolved to a lifeform resembling a primate. (TNG: "Genesis") She gave birth to the child in 2371. (Star Trek Generations)

Ogawa was not pregnant by the time of Star Trek Generations, so it can be assumed that the child was born sometime prior to that film. The child's gender was never revealed.

Ogawa was first seen in TNG: "Future Imperfect" as part of Riker's illusory future. Although actress Patti Yasutake believed she would not be called back after this episode, the character appeared again, this time with a first name, in "Clues" (although credited simply as "Nurse") and was given a last name in "Cause and Effect". Yasutake wasn't originally scheduled to appear in the fifth season episode "The Game" as the original call sheet features Wil Wheaton and two background performers during this turbolift scene, filmed on Friday 30 August1991 on Paramount Stage 9.

In 1993, Hallmark aired a television commercial in North America featuring Patti Yasutake in the role of Nurse Alyssa Ogawa, who is seen questioning the shipboard computer about the features of the USS Enterprise-D "Keepsake" ornament.